I've had problems getting this app to work for some time now.
Thanks Wally, you pointed me in the right direction advising looking into Documents\Assetto Corsa\logs\py_log.txt
I'm presuming there was a conflict with an older version of this app. I just had to rename/remove the
Documents\Assetto Corsa\cfg\apps\helicorsa.ini file and on next load it would be re-created and it's started appearing ingame correctly again.